SPECIAL ANATOMY. 65 



globular on the removal of pressure. The hepatic cells contain a fine, 



granular matter, fine and large oil-globules, and a round, nucleolated 



nucleus. 



Of the Geneuative Apparatus. 



All the terrestrial Gasteropoda under consideration are monoecious 

 or hermaphroditic, though none are capable of self-impregnation. They 

 are also mostly oviparous. 



Their genital system is complicated, and liable to such variation in 

 its details as to furnish excellent generic and specific characters. I 

 have therefore, when possible, given descriptions of the system in the 

 descriptive portion of my work, under each species. I will here give 

 only a general description of the development of the system : — The tes- 

 ticle is a single globular mass of aciniform cceca in some genera ; in 

 others it is composed of numerous fasciculi of long coeca : it is free, or 

 imbedded in the upper lobe of the liver ; its position, as well as the 

 shape of its cceca, being different in the respective genera. 



The epididymis is an undulated, or moderately tortuous tube, lead- 

 ing from the testicle to the inner side of the junction of the ovary with 

 the prostate gland. It opens into a groove upon the inner side of the 

 interior of the oviduct, which is continuous, at its inferior extremity, 

 with the vas deferens. Opening into the termination of the epididy- 

 mis, and lying against the inner side of the ovary, is a small, compound, 

 follicular body, which appears to be common to all the teiTestrial Gas- 

 teropoda, and is known as the accessory gland of the epididymis. The 

 prostate gland is a white or cream-colored body, occupying the inner 

 side of the whole length of the oviduct. It has a transverse, striated 

 appearance, and numerous openings into the groove leading from the 

 epididymis to the vas deferens. 



The vas deferens is a comparatively short tube, passing from the 

 prostate gland to the penis sac. The position of its junction forms a 

 specific character; sometimes it joins the summit of the latter, at 

 others it enters near the base. 



The penis sac is generally a long, cylindroid, irregular body, lying at 

 the right anterior part of the visceral cavity, and joining at its termina- 

 tion a short cloaca. Its form is, however, very variable, and is an ex- 

 cellent specific character, as is also the point of insertion of the retractor 

 muscle, which has its origin from the muscular investment of the vis- 

 ceral cavity, just posterior to the position of the pulmonary cavity. 

 The penis sac often has a flagellate appendage containing the curious 



